In general, keratin-containing fibers, for example hair, wool or pelts, are dyed either with substantive dyes or with oxidation dyes which are formed by oxidative coupling of one or more primary intermediates with one another or with one or more secondary intermediates. Primary and secondary intermediates are also known as oxidation dye precursors.
The primary intermediates normally used are primary aromatic amines containing another free or substituted hydroxy or amino group in the para or ortho position, diaminopyridine derivatives, heterocyclic hydrazones, 4-aminopyrazolone derivatives and 2,4,5,6-tetraamino-pyrimidine and derivatives thereof.
Special representatives are, for example, p-phenylenediamine, p-toluylenediamine, 2,4,5,6-tetraaminopyrimidine, p-aminophenol, N,N-bis-(2′-hydroxyethyl)-p-phenylenediamine, 2-(2′,5′-diaminophenyl)-ethanol, 2-(2′,5′-diaminophenoxy)-ethanol, 1-phenyl-3-carboxyamido-4-amino-5 pyrazolone, 4-amino-3-methylphenol, 2-aminomethyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, 2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine and 2,5,6-triamino-4-hydroxypyrimidine.
The secondary intermediates used are generally m-phenylene-diamine derivatives, naphthols, resorcinol and resorcinol derivatives, pyrazolones, m-aminophenols and substituted pyridine derivatives. Particularly suitable secondary intermediates are α-naphthol, 1,5-, 2,7- and 1,7-dihydroxynaphthalene, 5-amino-2-methylphenol, m-aminophenol, resorcinol, resorcinol monomethyl ether, m-phenylenediamine, 2,4-diaminophenoxyethanol, 2-amino-4-(2′-hydroxyethylamino)-anisole, 1-phenyl-3-methyl-5-pyrazolone, 2,4-dichloro-3-aminophenol, 1,3-bis-(2′,4′-diaminophenoxy)-propane, 2-chlororesorcinol, 4-chlororesorcinol, 2-chloro-6-methyl-3-aminophenol, 2-methyl resorcinol, 5-methyl resorcinol 3-amino-6-methoxy-2-methylaminopyridine and 3,5-diamino-2,6-dimethoxypyridine.
With regard to other typical dye components, reference is specifically made to the series entitled “Dermatology” (Editors: Ch. Culnan and H. Maibach), Marcel Dekker Inc., New York/Basel, 1986, Vol. 7, Ch. Zviak, The Science of Hair Care, Chapter 7, pages 248-250 (Substantive Dyes) and Chapter 8, pages 264-267 (Oxidation Dyes) and to the “Europäische Inventar der Kosmetik-Rohstoffe” published by the European Commission and available on floppy disk from the Bundesverband Deutscher Industrie—und Handelsunternehmen für Arzneimittel, Reformwaren und Körperpflegemittel e.V., Mannheim, Germany.
Although intensive colors with good fastness properties can be obtained with oxidation dyes, the color is generally developed under the influence of oxidizing agents, such as H2O2 for example, which in some cases can result in damage to the fibers. In addition, some oxidation dye precursors or certain mixtures of oxidation dye precursors can occasionally have a sensitizing effect in people with sensitive skin. Although substantive dyes are applied under more moderate conditions, their disadvantage is that, in many cases, the colors obtained often have inadequate fastness properties.
The use of the special components described in more detail hereinafter for coloring keratin-containing fibers has not hitherto been known.